The present invention relates to a paraocclusive dental instrument including two adjustable holding jaws to be attached to the lower dental arch and a basic element in communication with these holding jaws in the form of a rod or the like. The instrument is provided to transfer the movement of the lower jaw to display and/or recording devices.
In order to detect damage to the mandibular joint and to detect the movement behavior of the lower jaw with reference to the upper jaw during normal chewing, paraocclusive instruments are often employed to pick up the movement of the lower jaw. These are instruments equipped with holding jaws which, themselves, are fastened to the exterior of the lower dental arch by means of an adhesive and a compensating substance. The movement of the basic element of the paraocclusive instrument which follows the movement of the lower jaw is detected mechanically or electronically and is displayed and/or recorded, with a conclusion as to, for example, damage to the mandibular jaw or malocclusions or faulty tooth formations from such a visible display of the movement behavior. By application of the holding jaws of the instrument to the exterior of the lower dental arch, the influence emanating from this instrument due to contact between the teeth of the lower jaw and the teeth of the upper jaw in the plane or area of the occlusion is substantially suppressed and measurements can be made which are true-to-life during speaking or chewing.
Prior art paraocclusive instrument have been produced, analogously to dental prostheses, as individual specimens adapted to the shape of the lower dental arch of the respective patient and in which the holding jaws are combined with the basic element to form a one-piece structure. The manufacture of such paraocclusive instruments is very labor intensive which results not only in high costs but also requires undesirable waiting periods.
A paraocclusive instrument is known (ZWR-Das Deutsche Zahnarzteblatt [The German Dentist periodical]8/1987, page 702-704) which includes two sickle-shaped holding jaws that are combined into an arch which follows the lower dental arch, with outwardly projecting stubs being provided at the adjacent ends of the two holding jaws. These stubs are connected with one another by two parallel dual-thread screws which set the spacing and the mutual angular position of the two stubs and thus also set the holding jaws. One of these stubs is provided with an extending rod. Although this paraocclusive instrument can be adapted to various shapes and sizes of the lower jaw, the manipulations of both dual-thread screws required to accomplish this demand considerable skill since these two screws are disposed in the immediate vicinity of the holding jaw, which lies against the lower dental arch and since an adjustment of one the two dual-thread screws influences the other. Moreover, with the given shape of the holding jaws, in many cases it is possible to realize only a rough match to the shape of the dental arch. Thus, this prior art paraocclusive instrument is often adjusted on a model of the respective patient's lower jaw and an individual insert produced from a preliminary impression is attached to the interior of the holding jaws so that the use of this prior art instrument, in spite of its adjustability, is still very labor intensive.